gravity hot water not working

Mike T., Swampeast MO

Still working via gravity?

If so, there's usually an open expansion tank as the high point in the system as opposed to a closed compression tank in the basement. The old open expansion tank in the attic is usually replaced with a closed compression tank when the system is converted to forced flow.

Bottom-bottom connections are the most common for gravity systems unless it uses an overhead supply main.

Make certain that you get water from the 3rd floor rad when you bleed. After system runs for a while re-bleed EVERY radiator.

If there is a circulator, make certain that it's actually functioning.

What heats the ground floor? Sounds unusual for a gravity system to only heat the upper two floors of a three-floor structure. If ground floor rads have been removed do you have a lot of "dead" piping?

Under gravity circulation, and presuming that the system is full, it would be more common for the highest floor to overheat as motive force is highest up there...

DJF_2

gravity pain in the....

I looked at a gravity sys with one rad not working.There are5 rads alltogether,4on the2nd fl,1 on the 3rd.The one on the 3rd is not heating this year.The sys has worked fine for at least 10 yrs.There is a compresion tank on the boiler in basement.I pulled rad to check valve and for any orofice.The valve is ok,and no orofice.I disconected sup &ret at boiler header and flushed through rad with a hose,a little sedament came out and water ran fine.I filled sys,bleed rads,from bottom up.STILL NO HEAT!Sup &ret are on bottom of rads.ANY IDEAS????